1. Field of the Invention
This invention relates to apparatus as for winding magnetic tape into cassette cases with guard panels, and especially relates to apparatuses which extract leader tape from a cassette case, connect magnetic tape between the leader tape, and wind the tape onto a hub inside the cassette case.
2. Description of the Related Art
There are two basic production methods for magnetic recording tape cassettes. The first method involves loading cassette cases with reel hubs which have already been wound with magnetic tape outside the case. This method requires a large complex apparatus, but the magnetic tape winding time is short, and the processing rate is high. This method is suitable for large scale production facilities.
In the second method, cassettes are prepared by loading reel hubs joined by a length of leader tape into cassette cases. Leader tape is extracted from each cassette case, magnetic tape is connected to the leader tape, and a hub is rotated to wind magnetic tape into the cassette case. This method has a characterisitc in that it can be performed with a small simple apparatus. An apparatus which winds magnetic tape by the second method is described in Japanese Patent Publication No. 45203/1977. In this apparatus, as shown in FIG. 9, leader tape 92 is extracted from the cassette case 91, and attached to the first 93 and second 94 tape retainers. The leader tape 92 is cut between the first 93 and second 94 tape retainers to which it is attached, and the third tape retainer 95, which moves as a unit with the second tape retainer 94, and holds magnetic tape 96, is moved next to the first tape retainer 93. Magnetic tape 96 is connected to the end of the leader tape 92, the tape is released from the first 93 and third 95 tape retainers, and the hub inside the cassette case is rotated to wind up the tape. After a given length of magnetic tape 96 has been wound, it is again attached to, and cut between, the first 93 and third 95 tape retainers. The second 94 and third 95 tape retainers are then moved, such that the second tape retainer 94 is put next to the first tape retainer 93, the end of the magnetic tape 96 is joined to the previously cut end of the leader tape 92, and the remaining extracted tape is wound into the cassette case.
In addition to this, an apparatus with a different system of supplying magnetic tape to the severed leader tape has also been developed (Japanese Patent Publication No. 30444/1974). In this apparatus as well, leader tape is extracted from the cassette case, the leader tape is cut, and magnetic tape is joined to one end. After magnetic tape is wound into the cassette case, it is cut, and joined to the other end of the leader tape.
In former models that cut leader tape at a midpoint and splice it to magnetic tape, the leader tape extraction system is constructed such that the magnetic tape convieniently utilizes one of the cassette case's internal tape tracking guides during the winding process. In other words, although magnetic tape is wound into the cassette case by tracking over one of the winding system's extraction guides or rollers, which is external to the cassette, it also tracks over the cassette case's internal tape guide, which is utilized during normal tape recording and playback. The winding system's extraction guides can be accurately machined precision equipment, which can track tape at high speeds without tape damage. The cassette case's internal tape guides, however, are restricted costwise, and therefore, cannot be precision machined.
For this reason, high speed magnetic tape winding processes, which utilize a cassette case internal tape guide, have a the drawback in that tape is easily damaged during winding, and high speed even winding is impossible.
Magnetic tape which is not evenly wound has uneven edges which protrude from the wound roll and hit the inside wall of the cassette case during movement or transport. This shock either breaks the edge of the tape or otherwise bends, scratches, or damages the tape.